The present disclosure relates to conveying systems and methods, and in particular to conveying systems and methods of associating data with items being transported by a conveying system.
Conveying systems are used for a variety of purposes. Exemplary conveying systems include packaging systems, order fulfillment systems, manufacturing systems, shipping sortation systems, and returns processing systems. Some conveying systems use centralized multi-horsepower AC motors to drive shafts, belts or chains that, in turn, move banks of rollers to transport items throughout the conveying system. Other conveying systems include rollers with internal DC “micro-horsepower” motors that drive a localized segment of rollers. The latter systems include brushless DC roller conveying systems. A brushless DC roller conveying system includes several components and features, such as drive rollers with self-contained brushless DC motors, intelligent local controllers, and networking between the controllers based on bidirectional communication protocols.
Brushless DC roller conveying systems can be controlled by local controllers that control local functions in each of a plurality of zones of the conveying system and a centralized controller that tracks “items” (such as corrugated boxes, plastic totes, or pallets) as the items are transported through the conveying system. The centralized controllers tracks items by uniquely identifying the items at decision points in the conveyor system. These decision points include, for example, diverts, transfers, merges, order picking zones, weighing, sortation, and printing.
To uniquely identify the items, the conveyor systems often use bar codes that are printed on adhesive labels that are adhered to the items. Alternatively, a permanent bar code label on a reusable tote could be temporarily assigned to item(s) contained within the tote. The bar code associated with the permanent label is re-assigned when the items within the tote are changed.
As items are transported throughout the conveyor system, bar code scanners are positioned at decision points to read the bar codes. At each decision point, the bar code information is electronically sent to the centralized controller. The centralized controller determines operations to be performed for the item or data to be transmitted to the barcode scan location. This methodology is sub-optimal for a variety of reasons. For example, equipment capable of reading bar codes on moving items is expensive and can represent a large percentage of the cost of a conventional automated conveyor system. In addition, bar code scanners throughout the conveying system are in communication with the central control system, which may result in extensive and expensive data communication networks and associated cabling. Moreover, information required at decision points is stored in a central database. Timely access to that database can become challenging on large automated conveyor systems because the central controller must service all decision points simultaneously.
The bar codes used in conventional automated conveyor systems are one-dimensional bar codes that uniquely identify the item. However, one-dimensional bar codes do not contain any additional data about the item. Instead, data that determines the functions to be performed by the conveying system is stored remotely in a database associated with the centralized controller. This data can include routing information, order data, sort points, return points, or the like.
In a conventional conveying system, an item having an affixed one-dimensional bar code is transported by the conveying system. The conveying system includes a first zone and a second zone, where each zone includes a conveyor section that transports items, a bar code reader configured to scan bar codes affixed to the items, and a local controller. The conveying system further includes a centralized controller and a centralized database. The bar code reader scans the bar code for an item when the item enters the corresponding zone and transmits the bar code information to the local controller. The local controller retransmits the bar code information to the centralized controller for processing based on the operation for the particular zone. For example, if the first zone includes a scale, the centralized controller could send an expected weight for the item identified by the bar code information to the local controller for the first zone for comparison with the actual weight of the item. If the second zone includes a label printer, the centralized controller will send information to the local controller for the second zone to cause the label printer to print an appropriate label for the item.
One problem with such systems is that the one-dimensional bar code does not allow information to be passed from one zone to another. Moreover, the information in the one-dimensional bar code cannot be updated. In addition, as stated before, the centralized controller can become a bottleneck for information transfer throughout the conveying system. Finally, bar code readers are required at every zone in such conveying systems, which is a significant cost for the conveying system and can slow down operation of the system to allow items to be scanned.
A similar conveying system including items with RFID tags have been implemented. Such conveying systems allow information to be transferred from one zone to another (by writing information to the RFID tag). However, including RFID tags with every item can increase expenses significantly for large systems. Even in conveying systems in which RFID tags can be reused, RFID tags can only be written a predefined number of times before they fail to operate reliably. Moreover, such systems require RFID tag readers at every zone, which is a significant expense and can slow down operation of the system to allow tags to be scanned.
The use of two-dimensional bar codes has allowed additional data to be passed along with the item. For example, two-dimensional bar codes can include data about a predefined route of a specific item within the automated conveyor system. However, two-dimensional bar codes cannot be updated, thereby limiting the ability to update the data stored therein.